/* CSS Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #23aeb3;
    --secondary-color: #2e6771;
    --accent-color: #02385c;
    --bg-primary: #0a0a0a;
    --bg-secondary: #1a1a1a;
    --bg-tertiary: #2a2a2a;
    --text-primary: #ffffff;
    --text-secondary: #b3b3b3;
    --text-muted: #666666;
    --border-color: #333333;
    --shadow-color: rgba(0, 212, 255, 0.1);
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

/* Animated Background */
.animated-background {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -2;
    background: linear-gradient(45deg, #0a0a0a, #1a1a1a, #0a0a0a);
    background-size: 400% 400%;
    animation: gradientShift 15s ease infinite;
}

.gradient-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at 20% 80%, rgba(0, 212, 255, 0.1) 0%, transparent 20%),
                radial-gradient(circle at 80% 20%, rgba(255, 107, 53, 0.1) 0%, transparent 20%);
    animation: overlayShift 20s ease infinite;
}

.bg-canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none; /* keep UI interactive */
}

@keyframes gradientShift {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

@keyframes overlayShift {
    0%, 100% { opacity: 0.3; }
    50% { opacity: 0.1; }
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(10, 10, 10, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: all 0.3s ease;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.lang-toggle {
    padding: 0.5rem 0.9rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    font-weight: 600;
    cursor: pointer;
}

.lang-toggle:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

.nav-links a:hover {
    color: var(--primary-color);
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: width 0.3s ease;
}

.nav-links a:hover::after {
    width: 100%;
}

/* Container and Layout */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

.section {
    padding: 6rem 0;
    position: relative;
}

.section-alt {
    background: rgba(26, 26, 26, 0.5);
    backdrop-filter: blur(10px);
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 3rem;
    color: var(--text-primary);
    position: relative;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
    border-radius: 2px;
}

/* Hero Section */
.hero-section {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 80px;
}

.hero-content {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.hero-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

.highlight {
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 2.5rem;
    line-height: 1.6;
}

/* Hero Portrait */
.hero-portrait {
    display: block;
    width: 160px;
    height: 160px;
    object-fit: cover;
    border-radius: 50%;
    margin: 1rem auto 1.5rem;
    border: 2px solid var(--border-color);
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.875rem 1.75rem;
    border: none;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    color: white;
    box-shadow: 0 4px 15px var(--shadow-color);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px var(--shadow-color);
}

.btn-secondary {
    background: transparent;
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

.btn-secondary:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    transform: translateY(-2px);
}

.btn-small {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
    border-radius: 6px;
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    text-decoration: none;
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.btn-small:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

/* Social Links */
.social-links {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.social-links a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 50px;
    height: 50px;
    background: var(--bg-secondary);
    color: var(--text-secondary);
    border-radius: 12px;
    text-decoration: none;
    font-size: 1.25rem;
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.social-links a:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-3px);
    border-color: var(--primary-color);
}

/* CV Section */
.cv-content {
    display: grid;
    gap: 3rem;
}

.cv-section h3 {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    font-weight: 600;
}

.cv-item {
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: var(--bg-secondary);
    border-radius: 12px;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.cv-actions {
    display: flex;
    gap: 0.75rem;
    margin-top: 0.5rem;
}

.cv-item:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
    border-color: var(--primary-color);
}

.cv-item h4 {
    font-size: 1.125rem;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.cv-meta {
    color: var(--text-muted);
    font-size: 0.875rem;
    margin-bottom: 0.75rem;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1rem;
}

.skill-item {
    padding: 0.75rem 1rem;
    background: var(--bg-tertiary);
    border-radius: 8px;
    text-align: center;
    font-weight: 500;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.skill-item:hover {
    background: var(--primary-color);
    transform: translateY(-2px);
}

/* Publications */
.publications-grid {
    display: grid;
    gap: 2rem;
    max-width: 800px;
    margin: 0 auto;
}

.publication-card {
    background: var(--bg-secondary);
    padding: 2rem;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.publication-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    border-color: var(--primary-color);
}

.publication-card h3 {
    font-size: 1.25rem;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
}

.publication-meta {
    color: var(--primary-color);
    font-size: 0.875rem;
    margin-bottom: 1rem;
    font-weight: 500;
}

.publication-abstract {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    line-height: 1.7;
}

.publication-links {
    display: flex;
    gap: 1rem;
}

/* Projects */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.project-card {
    background: var(--bg-secondary);
    padding: 2rem;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.project-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    border-color: var(--primary-color);
}

.project-card h3 {
    font-size: 1.25rem;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.project-card p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    line-height: 1.7;
}

.project-tech {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.tech-tag {
    padding: 0.25rem 0.75rem;
    background: var(--bg-tertiary);
    color: var(--primary-color);
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 500;
    border: 1px solid var(--border-color);
}

.project-links {
    display: flex;
    gap: 1rem;
}

/* Contact Section */
.contact-content {
    text-align: center;
    max-width: 600px;
    margin: 0 auto;
}

.contact-content p {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
    line-height: 1.7;
}

.contact-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* Footer */
.footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: 2rem 0;
    text-align: center;
}

.footer .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.footer p {
    color: var(--text-muted);
}

.footer-links {
    display: flex;
    gap: 1rem;
}

.footer-links a {
    color: var(--text-muted);
    font-size: 1.25rem;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: var(--primary-color);
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-container {
        padding: 1rem;
    }
    
    .nav-links {
        gap: 1rem;
    }
    
    .nav-actions {
        margin-left: auto;
    }

    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.125rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .container {
        padding: 0 1rem;
    }
    
    .section {
        padding: 4rem 0;
    }
    
    .publications-grid,
    .projects-grid {
        grid-template-columns: 1fr;
    }
    
    .skills-grid {
        grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    }
    
    .footer .container {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .nav-links {
        display: none;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .section-title {
        font-size: 1.75rem;
    }
}

/* Smooth animations and hover effects */
* {
    transition: color 0.3s ease, background-color 0.3s ease, border-color 0.3s ease, transform 0.3s ease;
}

/* Loading animation for buttons */
.btn:active {
    transform: scale(0.98);
}

/* Focus states for accessibility */
.btn:focus,
.nav-links a:focus,
.social-links a:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}